1. Field of the Invention
The present invention relates to an IP telephone system for performing centralized control and operation of all the IP terminals installed at each lodgment, and in particular, it relates to an IP telephone system, in which duplexing of a main control device configuring an IP exchange, N+1 redundancy of a signal control device, and duplexing of a circuit are attempted and a back up exchange is installed at each lodgment, so that a backup is performed for a device trouble and a circuit fault, thereby enhancing reliability of the system operation
2. Description of the Related Art
In a conventional exchange, an IP exchange (TM portion) comprising an IP call control portion (SC portion) performing a call control of an IP terminal through a circuit (network) such as a LAN and the like, and an exchange control portion (CC portion) for performing a data exchange control of the IP call control portion (SC portion) and storing the IP terminal through a HUB is disclosed in Japanese Patent Application No. 2004-229112.
The IP exchange (TM portion) thus configured is also capable of mounting a plurality of IP terminals according to a connecting processing capacity (the number of sets of the IP terminals) of the IP terminals to be stored.
However, even if the conventional IP exchange (TM) assumes a number of IP terminals stored in the IP call control portion (SC portion) as one lodgment, when a trouble of the IP exchange (MT) or a fault of the circuit occurs, there is a possibility of all the IP terminals inside the lodgment becoming unable to operate, and in case the lodgment is divided into branch offices or sales offices of the region, there is a first problem that this causes an obstacle to sales activity.
Further, in case the conventional IP exchange (TM) provides a plurality of IP call control portions (SC portions) and each IP call control portion (SC portion) is stored with a number of IP terminals through a circuit (network), and a number of IP terminals stored for each IP call control portion (SC portion) are configured as one lodgment, when a common message such as lump information and the like is transmitted to all the IP terminals of each lodgment from the IP exchange (TM), it is necessary to convert the common message into a multicast message and transmit it to all the IP terminals.
However, in case the IP terminal which becomes a transmission target of the multicast message increases extremely in number, a data amount of the common message also inevitably increases, and there is a second problem in that a traffic amount of the load and the circuit (network) of the IP exchange (TM) becomes enormous.
Further, since the conventional IP exchange (TM) is single in exchange control portion (CC portion), when a trouble occurs in the IP call control portion (SC portion), there is a third problem in that the entire system breaks down in case the IP telephone system is configured by storing a number of IP terminals in a plurality of IP call control portions (SC portions), respectively.
Further, when assuming a case where a plurality of IP call control portions (SC portions) are stored with a number of IP terminals respectively, and a lodgment having a plurality of IP terminals is provided for each IP call control portion (SC portion), in case the IP call control portion (SC portion) develops a trouble, the operation of the lodgment in charge of this IP call control portion (SC portion) is no longer possible.
Further, since the conventional IP exchange (TM) is connected to the circuit (network) of one system with the IP call control portion (SC portion) of one system, when a fault occurs in a LAN port of the IP call control portion (SC portion), there is a fourth problem in that a plurality of IP terminals stored in the IP call control portion (SC portion) become all not usable.
Further, in case the conventional IP exchange (TM) is mounted with a plurality of IP call control portions (SC portions), each of which stores a number of IP terminals, there is a fifth problem in that a number of IP terminals stored in this IP call control portion (SC portion) are plunged into a inoperative state when a trouble occurs in one set IP call control portion (SC portion).